GBR WITH AN E-PTFE MEMBRANE-ASSOCIATED WITH DFDBA - HISTOLOGIC AND HISTOCHEMICAL ANALYSIS IN A HUMAN IMPLANT RETRIEVED AFTER 4 YEARS OF LOADING

As a result of a fracture to the cemented post and core, a pure titani um implant was extracted from a 54-year-old patient after 4 years of c linical loading. At implantation, the implant was positioned into an e xtraction socket and the defect was treated with an e-PTFE membrane as sociated with a DFDBA graft At retrieval the implant underwent histolo gic and histochemical examination to assess the characteristics of the regenerated bone after 4 years of prosthetic loading. The implant sho wed an angular bony defect at the smooth collar, but the bone-implant direct contact rate seemed to be elevated in the remaining implant sur face. Normal transmitted and polarized light examinations demonstrated that most of the DFDBA particles were resorbed and substituted by vit al newly formed bone. The regenerated bone appeared compact with secon dary osteons and large haversian canals; however; some partially miner alized remnants residuated in the spaces between the osteons. Within t he limits of this study the authors concluded that DFDBA can be substi tuted by the host bone, but the rate of substitution is very slow and not complete after 4 years. From a clinical point of view however; the load-bearing capacity of the bone regenerated with the membrane techn ique associated with DFDBA appeared to be similar to that of normal bo ne.